Whether choler or bile is the cause of a short lifespan.

One inquires further whether choler or bile is the cause of a short lifespan.

1. It seems not. That which ignites heat and consumes impurities is more the cause of a long lifespan than a short one. But choler is such as this, and therefore, etc.

2. Moreover, the four humors are analogous to the four elements. But of all the elements fire is especially incorruptible, as is said in the fourth book of On Meteorology. Therefore, similarly the humor also is analogous to fire. But such is choler, and therefore, etc.

The Philosopher says the opposite.

One must reply that choler (that is, fel) causes a short lifespan more than a long lifespan, when speaking per se, because that which consumes the radical moisture is not a cause of long life.8 But choler is of this sort. If it is intense, it burns the blood and consumes the other humors. Nevertheless, if the choler is tempered, it causes a long lifespan just as if removing an obstacle, because through its heat it tempers the cold of black bile and through its dryness tempers the moisture of phlegm. Choler that is collected in the gall bladder, however, is only a superfluity. Thus it can easily overflow and mix with the nearby parts, and this is said to be the cause of a short lifespan.

1. On to the arguments. To the first argument one must respond that that choler flowing inwardly with the blood and that which serves as nutrition for the choleric members by itself consumes the moistures. But that choler that is in the gall bladder is not of this type.

2. To the second argument one must reply that although fire is incorruptible [imputribilis] in and of itself, nevertheless fire causes other things to putrefy [putrescere], and this is why, etc. Or it suffers putrefaction [putrefit], as is evident in a tertian fever.

Whether serpents should have members that serve the motive power.

Next one inquires into the motive parts of animals. And first, whether serpents should have members that serve the motive power.

1. It seems so. This is because every bodily operation occurs through a mediating bodily organ. But progressive motion is a bodily operation. Therefore, it occurs through a mediating bodily organ.

2. Furthermore, every animal has some part for motion, by which it is held up when it is in motion. But that part is the instrument of motion, as is clear concerning the feet of animals. Therefore, there is such a part in serpents.

8. When A. says cholera sive fel"choler (that is, fel)"he seems to equate the two, another indication of the extent to which the two terms are confused.

The Philosopher says the opposite. For he says, "Serpents do not have feet," nor do they have wings, and these are the parts dedicated to local motion.

One must respond that serpents do not have parts dedicated to motion. And the reason is that there is a double operation in an animal. One occurs in one part only, as the first digestion occurs in the stomach and the second digestion in the liver. The other is found in individual parts, like the third digestion. But now it is true that that which deals with all the parts in an essential way determines no part exclusively for itself. But the motive power of the serpent is in every part of its body, and this is why the motive power in serpents does not have an organic part dedicated to itself.

1. On to the arguments. To the first, one should respond that every bodily operation occurs either with a body part mediating it or with the entire body mediating it, and the motion of serpents occurs in the second fashion.

2. To the second, one must respond that the serpent is not held up on a part dedicated for its motion, but when it raises its head, it holds itself up by the rest of its body and by its tail, and when it holds itself up on its head portion, the tail draws itself back in, and this is why it is unnecessary for it to have feet. The Philosopher's argument, however, is that, from the fact that something has blood, it should have either two or four feet. But neither two nor four feet would be adequate for the serpent, owing to the length of its body, because they would either be distant from one another, or not. If distant, then the intermediate parts would be unsupported. If not, then the extremities would be unsupported.